U.S. patent application number 17/178716 was filed with the patent office on 2021-08-19 for semiconductor device, photoelectric conversion device, photoelectric conversion system, transport apparatus, and control method of semiconductor device.
The applicant listed for this patent is Canon Kabushiki Kaisha. Invention is credited to Eiki Aoyama, Takuya Minakawa.
Application Number | 20210255292 17/178716 |
Document ID | / |
Family ID | 1000005444868 |
Filed Date | 2021-08-19 |
United States Patent
Application |
20210255292 |
Kind Code |
A1 |
Aoyama; Eiki ; et
al. |
August 19, 2021 |
SEMICONDUCTOR DEVICE, PHOTOELECTRIC CONVERSION DEVICE,
PHOTOELECTRIC CONVERSION SYSTEM, TRANSPORT APPARATUS, AND CONTROL
METHOD OF SEMICONDUCTOR DEVICE
Abstract
A semiconductor device comprising an integrated circuit is
provided. The integrated circuit comprises a first element
configured to execute a predetermined operation, a second element,
and a controller configured to perform control of setting the
second element in a non-operation state in a case in which
performance deterioration of the first element is a first degree
and operating the second element in a case in which the performance
deterioration of the first element is a second degree larger than
the first degree.
Inventors: |
Aoyama; Eiki; (Saitama,
JP) ; Minakawa; Takuya; (Toyko, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Canon Kabushiki Kaisha |
Tokyo |
|
JP |
|
|
Family ID: |
1000005444868 |
Appl. No.: |
17/178716 |
Filed: |
February 18, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 27/14609 20130101;
G01S 7/497 20130101 |
International
Class: |
G01S 7/497 20060101
G01S007/497; H01L 27/146 20060101 H01L027/146 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 19, 2020 |
JP |
2020-026468 |
Nov 19, 2020 |
JP |
2020-192667 |
Claims
1. A semiconductor device comprising an integrated circuit, wherein
the integrated circuit comprises: a first element configured to
execute a predetermined operation; a second element; and a
controller configured to perform control of setting the second
element in a non-operation state in a case in which performance
deterioration of the first element is a first degree and operating
the second element in a case in which the performance deterioration
of the first element is a second degree larger than the first
degree.
2. The device according to claim 1, wherein the integrated circuit
includes a plurality of second elements, and the controller changes
the number of second elements to be operated in the plurality of
second elements between a case in which the performance
deterioration of the first element is the second degree and a case
in which the performance deterioration of the first element is a
degree between the first degree and the second degree.
3. A semiconductor device comprising an integrated circuit, wherein
the integrated circuit comprises: a first element configured to
execute a predetermined operation; a second element; and a
controller configured to perform control of operating the second
element in a case in which a deterioration signal representing
performance deterioration of the first element is received and
setting the second element in a non-operation state in a case in
which the deterioration signal is not received.
4. The device according to claim 3, wherein the integrated circuit
includes a plurality of second elements, the deterioration signal
is a multi-valued signal corresponding to the performance
deterioration of the first element, and the controller changes the
number of second elements to be operated in the plurality of second
elements based on the deterioration signal corresponding to the
performance deterioration of the first element.
5. The device according to claim 3, wherein the case in which the
deterioration signal is not received is a case in which a signal
representing that the performance deterioration of the first
element is small as compared to a case in which the deterioration
signal is generated is received.
6. The device according to claim 3, wherein the integrated circuit
further includes a third element, and the deterioration signal
includes a signal representing a state of the third element.
7. The device according to claim 3, wherein the integrated circuit
further includes a monitor circuit configured to monitor a state of
the first element, and the monitor circuit supplies the
deterioration signal to the controller in accordance with a degree
of the performance deterioration of the first element.
8. The device according to claim 7, wherein the integrated circuit
further includes a fourth element configured to execute an
operation different from the predetermined operation, and the
fourth element is arranged in a region other than a region between
the first element and the monitor circuit.
9. The device according to claim 8, wherein a distance between the
fourth element and the monitor circuit is longer than a distance
between the first element and the monitor circuit.
10. The device according to claim 7, wherein the monitor circuit
includes an oscillation circuit, and the monitor circuit supplies
the deterioration signal to the controller in accordance with an
oscillation frequency of the oscillation circuit.
11. The device according to claim 1, wherein defining the
predetermined operation as a first operation and the controller as
a first controller, the integrated circuit further includes: a
fifth element configured to execute a second operation; a sixth
element; and a second controller configured to perform control of
setting the sixth element in the non-operation state in a case in
which performance deterioration of the fifth element is a third
degree and operating the sixth element in a case in which the
performance deterioration of the fifth element is a fourth degree
larger than the third degree.
12. The device according to claim 1, wherein defining the
predetermined operation as a first operation, the deterioration
signal as a first signal, the controller as a first controller, and
the monitor circuit as a first monitor circuit, the integrated
circuit further includes: a fifth element configured to execute a
second operation; a sixth element; and a second controller
configured to perform control of operating the sixth element in a
case in which a second signal representing performance
deterioration of the fifth element is received and setting the
sixth element in a non-operation state in a case in which the
second signal is not received.
13. The device according to claim 12, wherein a distance between
the first element and the first monitor circuit is shorter than a
distance between the fifth element and the first monitor
circuit.
14. The device according to claim 3, wherein the semiconductor
device further comprises an external monitor circuit configured to
monitor a state of the first element separately from the integrated
circuit, and the external monitor circuit supplies the
deterioration signal to the controller in accordance with a degree
of the performance deterioration of the first element.
15. The device according to claim 14, wherein the external monitor
circuit supplies the deterioration signal to the controller in
accordance with at least one of a temperature, an operating
voltage, a total current-carrying time, or a toggle rate of the
first element.
16. The device according to claim 1, wherein the first element
includes a clock buffer configured to constitute a clock tree, and
the second element includes an element configured to function as
the clock buffer.
17. The device according to claim 1, wherein the first element
includes a power shutdown switch configured to stop power supply to
some circuits in the integrated circuit, and the second element
includes an element configured to function as the power shutdown
switch.
18. The device according to claim 1, wherein the integrated circuit
operates in a plurality of operation modes, and the controller sets
the second element in the non-operation state every time the
operation mode switches from a first operation mode to a second
operation mode in the plurality of operation modes.
19. The device according to claim 18, wherein the integrated
circuit includes a plurality of second elements, and the controller
changes the number of second elements to be operated in the
plurality of second elements in accordance with each operation mode
in the plurality of operation modes.
20. A photoelectric conversion device comprising: a semiconductor
device defined in claim 1; and a photoelectric conversion unit in
which a plurality of pixels each including a photoelectric
conversion element configured to convert incident light into an
electrical signal are arranged.
21. The device according to claim 20, wherein a first element
includes a driving circuit configured to drive the photoelectric
conversion unit, and a second element includes an element
configured to function as the driving circuit.
22. The device according to claim 21, wherein the first element
includes an output buffer circuit arranged in the driving circuit,
and the second element includes an element configured to function
as the output buffer circuit.
23. The device according to claim 20, wherein the photoelectric
conversion device has a stacked structure including a first layer
with the photoelectric conversion unit, and a second layer with the
integrated circuit.
24. A photoelectric conversion system comprising: a photoelectric
conversion device defined in claim 20; an optical system configured
to form an image on a photoelectric conversion unit of the
photoelectric conversion device; and a signal processing unit
configured to process a signal output from the photoelectric
conversion device.
25. A transport apparatus comprising a driving device, comprising a
control device including a photoelectric conversion device defined
in claim 20 and configured to control the driving device based on
information obtained by the photoelectric conversion device.
26. A control method of a semiconductor device comprising an
integrated circuit including a first element configured to execute
a predetermined operation, and a second element, comprising:
performing control of setting the second element in a non-operation
state in a case in which performance deterioration of the first
element is a first degree; and operating the second element in a
case in which the performance deterioration of the first element is
a second degree larger than the first degree.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The present invention relates to a semiconductor device, a
photoelectric conversion device, a photoelectric conversion system,
a transport apparatus, and a control method of the semiconductor
device.
Description of the Related Art
[0002] A semiconductor device is incorporated and used in a
monitoring camera required to operate for a long time or an
in-vehicle camera required to have high reliability. To ensure the
long-time operation or high reliability of the semiconductor
device, a configuration for making an integrated circuit included
in the semiconductor device redundant has been examined.
International Publication No. 2012/056574 shows including a
plurality of semiconductor devices having the same configuration to
increase the redundancy. In International Publication No.
2012/056574, if the magnitude relation between a predetermined
threshold and a value obtained by measuring the physical
characteristic of an active semiconductor circuit during the
operation of the semiconductor circuit reverses, current carrying
to the active semiconductor circuit is stopped, and the
semiconductor circuit to be used is switched, thereby operating the
system for a long time.
SUMMARY OF THE INVENTION
[0003] It is necessary to operate a semiconductor device for a
longer time while ensuring higher reliability.
[0004] Some embodiments of the present invention provide a
technique advantageous in ensuring a long-time operation and high
reliability of a semiconductor device.
[0005] According to some embodiments, a semiconductor device
comprising an integrated circuit, wherein the integrated circuit
comprises: a first element configured to execute a predetermined
operation; a second element; and a controller configured to perform
control of setting the second element in a non-operation state in a
case in which performance deterioration of the first element is a
first degree and operating the second element in a case in which
the performance deterioration of the first element is a second
degree larger than the first degree, is provided.
[0006] According to some other embodiments, a semiconductor device
comprising an integrated circuit, wherein the integrated circuit
comprises: a first element configured to execute a predetermined
operation; a second element; and a controller configured to perform
control of operating the second element in a case in which a
deterioration signal representing performance deterioration of the
first element is received and setting the second element in a
non-operation state in a case in which the deterioration signal is
not received, is provided.
[0007] According to still other embodiments, a control method of a
semiconductor device comprising an integrated circuit including a
first element configured to execute a predetermined operation, and
a second element, comprising: performing control of setting the
second element in a non-operation state in a case in which
performance deterioration of the first element is a first degree;
and operating the second element in a case in which the performance
deterioration of the first element is a second degree larger than
the first degree.
[0008] Further features of the present invention will become
apparent from the following description of exemplary embodiments
(with reference to the attached drawings).
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a block diagram showing an example of the
configuration of a semiconductor device according to an
embodiment;
[0010] FIG. 2 is a flowchart showing an example of the operation of
the semiconductor device shown in FIG. 1;
[0011] FIG. 3 is a block diagram in a case in which the
semiconductor device shown in FIG. 1 is applied to a clock
tree;
[0012] FIG. 4 is a block diagram in a case in which the
semiconductor device shown in FIG. 1 is applied to a power shutdown
switch;
[0013] FIG. 5 is a block diagram in a case in which the
semiconductor device shown in FIG. 1 is applied to the driving
circuit of a photoelectric conversion device;
[0014] FIG. 6 is a block diagram in a case in which the
semiconductor device shown in FIG. 1 is applied to the driving
circuit of a photoelectric conversion device;
[0015] FIG. 7 is a block diagram showing a modification of the
semiconductor device shown in FIG. 1;
[0016] FIG. 8 is a block diagram showing an example of the
configuration of the monitor circuit of the semiconductor device
shown in FIG. 7;
[0017] FIG. 9 is a flowchart showing an example of the operation of
the monitor circuit shown in FIG. 8;
[0018] FIG. 10 is a block diagram showing an example of the
arrangement of the monitor circuit of the semiconductor device
shown in FIG. 8;
[0019] FIG. 11 is a block diagram showing another modification of
the semiconductor device shown in FIG. 1;
[0020] FIG. 12 is a block diagram showing still another
modification of the semiconductor device shown in FIG. 1;
[0021] FIG. 13 is a block diagram showing an example of the
arrangement of the monitor circuit of the semiconductor device
shown in FIG. 12;
[0022] FIG. 14 is a timing chart showing an example of the
operation at the time of switching of the operation mode of the
semiconductor device shown in FIG. 1;
[0023] FIG. 15 is a block diagram showing an example of the
configuration of an image capturing system incorporating the
semiconductor device shown in FIG. 1; and
[0024] FIGS. 16A and 16B are block diagrams showing an example of
the configuration of a transport apparatus including an image
capturing system incorporating the semiconductor device shown in
FIG. 1.
DESCRIPTION OF THE EMBODIMENTS
[0025] Hereinafter, embodiments will be described in detail with
reference to the attached drawings. Note, the following embodiments
are not intended to limit the scope of the claimed invention.
Multiple features are described in the embodiments, but limitation
is not made to an invention that requires all such features, and
multiple such features may be combined as appropriate. Furthermore,
in the attached drawings, the same reference numerals are given to
the same or similar configurations, and redundant description
thereof is omitted.
[0026] The configuration and operation of a semiconductor device
according to an embodiment of the present invention will be
described with reference to FIGS. 1 to 13. FIG. 1 is a block
diagram showing an example of the configuration of a semiconductor
device 100 according to this embodiment.
[0027] The semiconductor device 100 includes an integrated circuit
101. The integrated circuit 101 includes a circuit 102 including an
element configured to execute a predetermined operation, a circuit
103 having the same configuration as the circuit 102, and a
controller 105 that controls an element including the circuit 103
based on a signal 104 (deterioration signal) representing
deterioration of the performance of the element including the
circuit 102 during an operation. The circuit 102 is a circuit that
operates in a normal state independently of the degree of
performance deterioration such as a temporal change (for example,
degradation) caused by use of the semiconductor device 100. The
element included in the circuit 103 is in a non-operation state
until the degree of performance deterioration of the element
included in the circuit 102 for a predetermined operation becomes a
predetermined degree. On the other hand, if it is difficult for the
element included in the circuit 102 to execute the predetermined
operation due to a temporal change or the like, in other words, the
performance deterioration is larger than a predetermined degree,
the element included in the circuit 103 operates under the control
of the controller 105. That is, the circuit 102 is a redundancy
target circuit in the semiconductor device 100, and the circuit 103
is a redundant circuit arranged to ensure the redundancy of the
circuit 102. A description will be made below assuming that the
element included in the circuit 103 operates to ensure the
redundancy of the circuit 102 in accordance with characteristic
degradation (performance deterioration) of the element included in
the circuit 102 caused by a temporal change or the like.
[0028] The controller 105 is notified of the state of the circuit
102 by the signal 104 (deterioration signal). In accordance with
the signal 104, the controller 105 selects an element to be
operated in the circuit 103 via a control signal 106. For example,
concerning the circuit 102 including an element whose performance
has deteriorated, the circuit 102 and the element selected in the
circuit 103 by the controller 105 operate, thereby executing the
predetermined operation to be performed by the circuit 102. As will
be described later, the signal 104 may be generated in the
integrated circuit 101, or may be supplied from the outside of the
integrated circuit 101. In addition, the controller 105 may control
the state of the circuit 102 by the signal 104 and another signal.
The "another signal" is a signal (normal signal) representing that
the performance deterioration of the circuit 102 has not reached a
predetermined degree. That is, if the performance deterioration of
the element included in the circuit 102 has not reached a
predetermined degree, a normal signal is generated. The normal
signal is a signal representing that the performance deterioration
of the element included in the circuit 102 is smaller than that in
a case in which a deterioration signal is generated. If the
controller 105 receives the normal signal, the predetermined
operation by the circuit 102 is continued. On the other hand, if
the signal 104 is received, the controller 105 may select an
element to be operated in the circuit 103.
[0029] Details of the operation of the integrated circuit 101 will
be described next. FIG. 2 is a flowchart for explaining the
operation of the integrated circuit 101 of the semiconductor device
100 shown in FIG. 1.
[0030] When the operation is started by, for example, powering on
the device, the controller 105 repetitively performs reception wait
processing (step S201) and determination of the presence/absence of
reception of the signal 104 (step S202) to receive the signal 104.
The detailed form of the signal 104 does not matter, and, for
example, the signal 104 may be a binary signal that takes high
level when the performance of the element included in the circuit
102 has deteriorated, and takes low level otherwise. Alternatively,
for example, the signal 104 may be a multi-valued signal having a
plurality of bits corresponding to the degrees of progress of
performance deterioration of the element included in the circuit
102.
[0031] Upon receiving the signal 104, the controller 105 executes
processing (step S203) of generating the control signal 106 used to
select an element to be operated in the circuit 103. The detailed
form of the control signal 106 does not matter. For example, if the
signal 104 is a binary signal as described above, the control
signal 106 may be a binary signal that changes to high level when
an element included in the circuit 103 is used, and changes to low
level when an element included in the circuit 103 is not used. In
this case, all elements arranged in the circuit 103 can change to a
selection state and operate. Also, for example, each of the
circuits 102 and 103 may be formed by one element.
[0032] Concerning the control signal 106, a case in which the
signal 104 is a multi-valued signal as described above will be
examined. In this case, a storage unit that stores the multi-valued
control signal 106 corresponding to the multi-valued signal 104 may
be arranged in the controller 105, and the controller 105 may
select the control signal 106 according to the multi-valued signal
104 from the storage unit and supply it to the circuit 103. The
controller 105 may include a logic operation circuit capable of
generating the multi-valued control signal 106 corresponding to the
multi-valued signal 104. The controller 105 can thus generate the
multi-valued control signal 106 corresponding to the multi-valued
signal 104.
[0033] Next, the controller 105 executes control processing (step
S204) of controlling the element included in the circuit 103 by
supplying the control signal 106 to the circuit 103. If the control
signal 106 is a binary signal, control in two states can be
performed such that the circuit 103 is operated in addition to the
circuit 102, or the circuit 103 is not operated. If the control
signal 106 is a multi-valued signal, the types and number of
elements to be operated in the circuit 103 can appropriately be
selected in accordance with each signal.
[0034] FIG. 3 shows a case in which this embodiment is applied to a
circuit that forms a clock tree as the circuit 102 of the
semiconductor device 100. In general, when current carrying to the
integrated circuit 101 of the semiconductor device 100 is
performed, a phenomenon called NBTI (Negative Bias Temperature
Instability) or hot carrier injection occurs. It is known that this
causes an element degradation phenomenon that changes the threshold
voltage or ON current of a transistor. It is difficult to make a
design to satisfy a desired product life in consideration of the
degradation of the threshold voltage or ON current of a transistor
caused by current carrying.
[0035] One cause of making it difficult to make a design to satisfy
a desired product life is a fault in a circuit operation caused by
the degradation of a clock buffer that forms a clock tree in a
synchronization circuit. In a synchronization circuit design, a
clock tree is formed to supply a clock signal to a flip-flop
circuit in the circuit. In the synchronization circuit, the toggle
rate of the clock signal propagated by the clock tree is higher as
compared to a circuit that propagates another data signal, and the
progress of degradation caused by hot carrier injection can be
faster than that of the circuit that propagates the data signal.
Since the degradation progresses quickly, a normal clock signal
cannot be propagated to the flip-flop circuit in the
synchronization circuit, and an operation error of the
synchronization circuit may occur.
[0036] According to this embodiment, even if degradation occurs in
a clock buffer that is an element arranged the circuit 102 as the
redundancy target, a clock buffer that is an element arranged in
the circuit 103 for redundancy is used in combination. This makes
it possible to supply a normal clock signal to the flip-flop
circuit in the integrated circuit 101 of the semiconductor device
100. A detailed operation will be described below with reference to
FIG. 3.
[0037] The integrated circuit 101 of the semiconductor device 100
includes a clock tree 302 that is an example of the circuit 102
that is the redundancy target and operates in a normal state, and a
clock tree 303 that is an example of the circuit 103 used to make
the clock tree 302 redundant. The clock tree 302 includes a clock
buffer 304. The clock tree 303 includes a clock buffer 305
configured to function as a clock buffer in place of the clock
buffer 304 if the performance of the clock buffer 304 that is an
element included in the clock tree 302 has deteriorated, and a
clock buffer control switch 306.
[0038] The controller 105 supplies the control signal 106 to the
clock tree 303 in accordance with the signal 104 representing the
performance deterioration of the clock buffer 304 included in the
clock tree 302 that is an example of the circuit 102. By the
control signal 106, the clock buffer control switch 306 in the
clock tree 303 is controlled, and the clock buffer 305 to be used
for the operation is selected. Hence, the clock buffer 304 and the
clock buffer 305 can be used in parallel, and even if the degree of
performance deterioration becomes large in the clock buffer 304 of
the clock tree 302, clock propagation similar to that before the
performance deterioration of the clock buffer 304 can be
performed.
[0039] In the configuration shown in FIG. 3, only one line of clock
tree 303 configured to ensure redundancy is arranged. However, a
plurality of lines of clock trees 303 may be arranged. When a
plurality of lines of clock trees 303 are arranged, and the clock
buffer 304 and a plurality of clock buffers 305 are used in
parallel, a clock can be propagated in the integrated circuit 101
for a longer period even if degradation occurs in the clock buffer
304.
[0040] A case in which a power shutdown function arranged in the
semiconductor device 100 is the redundancy target will be described
next with reference to FIG. 4. The power shutdown function is a
technique aiming at suppressing a leakage current by stopping power
supply to some circuits (regions) that need not operate in the
integrated circuit 101 of the semiconductor device 100.
[0041] In a power shutdown switch 404 that controls power supply, a
voltage that sets the power shutdown switch 404 always in an ON
state is applied to the gate during a non-power shutdown (power
supply) period. If the power shutdown switch 404 is formed by a
PMOS switch, a negative bias is always applied to the gate during
the non-power shutdown period, and degradation by NBTI occurs. As a
result, the amount of a current that the power shutdown switch 404
can supply can temporally change in accordance with use of the
semiconductor device 100. The change of the current amount causes a
change of time until power feed to a power shutdown region 406 is
completed.
[0042] If the ON current of the power shutdown switch 404 becomes
small, the power feed time for the power shutdown region 406
becomes long. When the power feed time becomes long, the time until
the power shutdown region 406 recovers becomes long. If recovery is
not completed at a desired timing, an operation error of the power
shutdown region 406 occurs.
[0043] It is also considered that the ON current of the power
shutdown switch 404 becomes large, and the power feed time for the
power shutdown region becomes short. If the ON current of the power
shutdown switch 404 becomes large due to the occurrence of
degradation in the power shutdown switch 404, the amount of a
current flowing to the power shutdown region 406 in a unit time
becomes large when changing from a power shutdown state to a power
supply state. When the amount of the current flowing to the power
shutdown region 406 in a unit time becomes large, power supply
noise that changes the potential of a non-power shutdown region 410
may be generated. If the power supply noise is generated, an
operation error may occur in the non-power shutdown region 410.
[0044] According to this embodiment, even if degradation occurs in
the power shutdown switch 404 that is an element arranged the
circuit 102 as the redundancy target, the power shutdown switch
that is an element arranged in the circuit 103 for redundancy is
used in combination. This makes it possible to execute the power
shutdown function while suppressing an occurrence of a fault in the
circuit operation. A detailed operation will be described below
with reference to FIG. 4.
[0045] The integrated circuit 101 of the semiconductor device 100
includes a power shutdown switch group 402 that is an example of
the circuit 102 that is the redundancy target and operates in a
normal state, and a power shutdown switch group 403 that is an
example of the circuit 103 used to make the power shutdown switch
group 402 redundant. The power shutdown switch group 402 is formed
by one or a plurality of power shutdown switches 404. The power
shutdown switch group 403 is formed by one or a plurality of power
shutdown switches 405. Power supply to the power shutdown region
406 is controlled by the power shutdown switches 404 and 405.
[0046] The controller 105 supplies the control signal 106 to the
power shutdown switch group 403 in accordance with the signal 104
representing the performance deterioration of the power shutdown
switch 404 included in the power shutdown switch group 402 that is
an example of the circuit 102. By the control signal 106, the power
shutdown switch 405 that is an element to be operated in the power
shutdown switch group 403 is selected. Hence, the power shutdown
switch 404 and the power shutdown switch 405 can be used in
combination, and even if degradation occurs in the power shutdown
switch 404 of the power shutdown switch group 402, the power feed
time for the power shutdown region 406 can be controlled.
[0047] An example in which the semiconductor device 100 is applied
to a photoelectric conversion device 501 will be described next
with reference to FIG. 5. Another example of the cause of making it
difficult to make a design to satisfy a desired product life is a
fault in a circuit operation caused by performance deterioration of
an element included in a driving circuit configured to drive a
photoelectric conversion unit in which a plurality of pixels each
including a photoelectric conversion element are arranged in
photoelectric conversion device. The photoelectric conversion
device 501 performs image capturing by converting incident light
into an electrical signal by the photoelectric conversion elements.
If a driving circuit that generates a driving signal for the
photoelectric conversion unit temporally degrades, the driving
signal generation timing temporally changes. As a result, the
operation timing when performing image capturing such as
photoelectric conversion changes, and a fault that image capturing
at a desired timing is impossible may occur.
[0048] According to this embodiment, even if degradation occurs in
a driving circuit 511 that is the circuit 102 as the redundancy
target, a driving circuit 512 that is the circuit 103 for
redundancy is used in combination. This enables a circuit operation
at an appropriate timing in the photoelectric conversion device
501. A detailed operation will be described below with reference to
FIG. 5.
[0049] The photoelectric conversion device 501 shown in FIG. 5
includes a pixel circuit layer 520 including a photoelectric
conversion unit 523 in which pixels 522 each including a
photoelectric conversion element 524 are arranged in an array, and
a pixel driving circuit layer 510 that supplies a driving signal
516 to the pixel circuit layer 520. The pixel driving circuit layer
510 is an example of a layer including the integrated circuit 101
of the above-described semiconductor device 100. The pixel driving
circuit layer 510 includes the driving circuit 511 that is an
example of the circuit 102 as the redundancy target, and the
driving circuit 512 that is an example of the circuit 103 used to
make the driving circuit 511 redundant. In the configuration shown
in FIG. 5, the photoelectric conversion device 501 has a stacked
structure including the pixel circuit layer 520 with the
photoelectric conversion unit 523, and the pixel driving circuit
layer 510 with the integrated circuit 101. However, the structure
is not limited to this, and the photoelectric conversion unit 523
and the integrated circuit 101 including the driving circuit 512
may be arranged in the same layer.
[0050] In the pixel circuit layer 520, the pixels 522 arranged in
an array are connected to the driving circuit 511 by a driving
signal line 521 shared by the pixels 522 arranged in the lateral
direction (to be also referred to as a row direction or a
horizontal direction) shown in FIG. 5. The pixels 522 connected to
the common driving signal line 521 are controlled by the driving
signal 516 output from the driving circuit 511. By the driving
signal 516, the timing of driving is transmitted to the pixels 522
in the pixel circuit layer 520, and an electrical (charge) signal
generated by the photoelectric conversion element 524 can be
read.
[0051] In this embodiment, since the configuration of a process
after the pixels 522 convert light into an electrical signal does
not matter, it is expressed as the "pixel driving circuit layer
510", and a method of processing the electrical signal output from
each pixel 522 in the pixel circuit layer 520 is not described. As
the processing of the electrical signal output from the pixel 522,
various kinds of known processing can be applied.
[0052] Every time the electrical signal is output from the pixel
522, the driving circuit 511 that outputs the driving signal 516
temporally degrades, and the timing of output of the driving signal
516 from the driving circuit 511 temporally changes. The temporal
change changes the timing of reading the electrical signal from the
pixel 522. Hence, when the driving circuit 511 and the driving
circuit 512 that makes the driving circuit 511 redundant are used
in combination, the timing of reading the electrical signal from
the pixel 522 can be adjusted.
[0053] More specifically, the controller 105 supplies the control
signal 106 to the driving circuit 512 in accordance with the signal
104 representing the performance deterioration of the driving
circuit 511 that is an example of the circuit 102. By the control
signal 106, the driving circuit 512 that outputs a driving signal
517 is selected. Hence, the driving signal line 521 is driven using
the driving signal 516 supplied from the driving circuit 511 and
the driving signal 517 supplied from the driving circuit 512. The
driving circuit 512 is controlled by the control signal 106 output
from the controller 105, and the control timing may be controlled
by the signal 104. Alternatively, the control timing of the driving
circuit 512 may be controlled by a control circuit (not shown)
configured to drive the driving circuit 511. The control timings of
the driving circuit 511 and the driving circuit 512 may be
controlled by the same control circuit (for example, the controller
105).
[0054] In the above description, the driving circuit 511 is made
redundant. As shown in FIG. 6, the circuit may be made redundant in
the driving circuit 511. More specifically, an output buffer
circuit 533 that finally outputs the driving signal 516 from the
driving circuit 511 is set to the redundancy target, and the
driving signal 516 may be output by combining a buffer circuit 532
that is an element included in the circuit 103. The operation of
the buffer circuit 532 is controlled by a buffer circuit control
switch 531, and the buffer circuit control switch 531 is controlled
by the control signal 106 supplied from the controller 105. This
makes it possible to control the output timing of the driving
signal 516 even if the output buffer circuit 533 degrades.
[0055] In the above description, the driving circuits 511 and 512
are shown as the examples of the circuits 102 and 103 in the
photoelectric conversion device 501. However, the present invention
is not limited to this. For example, in the pixel driving circuit
layer 510 of the photoelectric conversion device 501, the
combination of the above-described clock trees 302 and 303 may be
arranged, or the combination of the power shutdown switch groups
402 and 403 may be arranged. The integrated circuit 101 of the
semiconductor device 100 can be applied to various configurations
of the photoelectric conversion device 501.
[0056] Additionally, in this embodiment, an image capturing device
has been described as an example of the photoelectric conversion
device 501 to which the semiconductor device 100 is applied.
However, the present invention is not limited to this, and the
semiconductor device can also be applied to another example of the
photoelectric conversion device. For example, the semiconductor
device 100 can be applied to a photoelectric conversion device such
as a distance measuring device (a device configured to measure a
distance using focus detection or TOF (Time Of Flight)) or a
photometric device (a device configured to measure an incident
light amount).
[0057] Generation of the signal 104 representing the state of an
element included in the circuit 102 during an operation will be
described next. FIG. 7 is a block diagram of the semiconductor
device 100 in a case in which the signal 104 is generated in the
integrated circuit 101. In the configuration shown in FIG. 7, the
integrated circuit 101 further includes a monitor circuit 700
configured to monitor the state of the element included in the
circuit 102 in addition the configuration shown in FIG. 1 described
above. The monitor circuit 700 generates the signal 104 in
accordance with the degree of performance deterioration of the
element included in the circuit 102, and supplies the signal 104 to
the controller 105.
[0058] As circuit configuration of the monitor circuit 700, various
known circuit configurations can be used. FIG. 8 is a block diagram
showing an example of the circuit configuration of the monitor
circuit 700. The operation of the monitor circuit 700 will be
described below.
[0059] In the configuration shown in FIG. 8, the monitor circuit
700 includes an oscillation circuit 804, and generates the signal
104 in accordance with a change of the oscillation frequency of the
oscillation circuit 804. Also, the monitor circuit 700 includes a
control circuit 802, a comparator 803, and a counter 805.
[0060] As the oscillation circuit 804, for example, a ring
oscillator circuit formed by multistage connection of an odd number
of inverters may be used. When a transistor that forms the
oscillation circuit 804 repeats switching, degradation occurs in
the transistor that forms the oscillation circuit 804, a change of
the ON current or a change of a threshold voltage occurs, and the
oscillation frequency changes. This allows the monitor circuit 700
to monitor (estimate) the state of the element included in the
circuit 102.
[0061] FIG. 9 is a flowchart showing an example of the operation of
the monitor circuit 700 to generate the signal 104 and supply it to
the controller 105. First, the control circuit 802 configured to
control the operation of the monitor circuit 700 performs
oscillation start notification processing (step S901) of supplying
an oscillation start signal 810 to the oscillation circuit 804. In
accordance with the oscillation start signal 810, the oscillation
circuit 804 performs oscillation start processing (step S902) of
starting oscillation.
[0062] When the oscillation circuit 804 starts oscillation, the
counter 805 performs count processing (step S903) of counting the
number of times of oscillation of an oscillation signal 811 output
from the oscillation circuit 804. The counter 805 notifies the
comparator 803 of a count result 812.
[0063] The comparator 803 stores, in advance, a value (to be
referred to as a relationship value hereinafter) of the oscillation
frequency of the oscillation circuit 804 according to the
relationship between the state of the element included in the
circuit 102 and the oscillation frequency (the number of times of
oscillation) of the oscillation circuit 804. The comparator 803
performs count result comparison processing (step S904) of
comparing the relationship value with the count result 812.
[0064] The comparator 803 determines (step S905) the state (the
degree of performance deterioration) of the element included in the
circuit 102 based on the result of the count result comparison
processing. As the result of count result comparison determination,
if the count does not reach a count representing that the
performance deterioration of the circuit 102 is a predetermined
degree, as compared to the relationship value (NO in step S905),
the process advances to count processing (step S903). If the count
reaches a count representing that the performance deterioration of
the circuit 102 is larger than the predetermined degree, as
compared to the relationship value (YES in step S905), the
comparator 803 executes degradation detection notification
processing (step S906) of supplying a degradation detection
notification signal 813 to the control circuit 802. Upon receiving
the degradation detection notification signal 813, the control
circuit 802 executes signal generation processing (step S907) of
generating the signal 104.
[0065] Here, if the relationship value is one value, the signal 104
can be the above-described binary signal. If two or more values
(for example, a value A and a value B) are provided as the
relationship values, the signal 104 can be a multi-valued signal
including a signal according to a count smaller than the value A, a
signal according to a count ranging from the value A (inclusive) to
the value B (exclusive), and a signal according to a count equal to
or larger than the value B.
[0066] The physical arrangement of the monitor circuit 700 in the
integrated circuit 101 will be described next with reference to
FIG. 10. Generally, in the integrated circuit 101, a gradient of
the voltage or temperature of a power supply occurs depending on
physical coordinate positions. The magnitude of the degradation of
an element such as a transistor included in the circuit 102 changes
depending on a condition such as a voltage or a temperature. Hence,
when the condition such as a voltage or a temperature for the
monitor circuit 700 is made close to that of the circuit 102 as the
redundancy target, the monitor circuit 700 can more correctly
detect the state of the element included in the circuit 102.
[0067] As shown in FIG. 10, consider a case in which the integrated
circuit 101 further includes a circuit 1000 configured to execute
an operation different from a predetermined operation executed by
the element included in the circuit 102. Depending on the power
consumption of the circuit 1000 different from the circuit 102, a
voltage supplied to an element arranged on the periphery of the
circuit 1000 may be different from that on the periphery of the
circuit 102. The temperature on the periphery of the circuit 102
and the temperature on the periphery of the circuit 1000 may also
be different. For this reason, if the distance between the circuit
1000 and the monitor circuit 700 becomes short, the condition such
as a voltage or a temperature in the monitor circuit 700 may be
greatly different from the condition such as a voltage or a
temperature in the circuit 102 and may be close to the condition
such as a voltage or a temperature in the circuit 1000. That is,
the monitor circuit 700 may be unable to correctly monitor the
state of the element included in the circuit 102.
[0068] Hence, the monitor circuit 700 is arranged such that
distance 2 between the monitor circuit 700 and the element included
in the circuit 1000 becomes longer than distance 1 between the
monitor circuit 700 and the element included in the circuit 102, as
shown in FIG. 10. Since the condition such as a voltage or a
temperature in the monitor circuit 700 and that in the element
included in the circuit 102 thus become close, the monitor circuit
700 can more correctly monitor the state of the element included in
the circuit 102.
[0069] The arrangement of each constituent element of the
integrated circuit 101 may be adjusted such that, for example, the
circuit 1000 is arranged in a region other than the region between
the monitor circuit 700 and the element included in the circuit
102. Alternatively, for example, the monitor circuit 700 may be
arranged to be adjacent to the circuit 102. When the monitor
circuit 700 is arranged to be adjacent to the circuit 102, the
condition such as a voltage or a temperature can be almost equal
between the element included in the circuit 102 and the element
included in the monitor circuit 700.
[0070] Arranging the monitor circuit 700 configured to monitor the
element included in the circuit 102 in the integrated circuit 101
in the configuration shown in FIG. 7 has been described. However,
the circuit configured to monitor the circuit 102 need not always
be arranged in the integrated circuit 101. As shown in FIG. 11, the
semiconductor device 100 may further include an external monitor
circuit 1100 configured to monitor the state of the element
included in the circuit 102 separately from the integrated circuit
101. The external monitor circuit 1100 generates the signal 104 in
accordance with the degree of performance deterioration of the
element included in the circuit 102, and supplies the signal 104
from the outside of the integrated circuit 101 to the controller
105 in the integrated circuit 101. The external monitor circuit
1100 monitors a state such as the magnitude of the degree of
degradation of the element included in the circuit 102 from the
outside of the integrated circuit 101, and generates the signal
104.
[0071] Various kinds of appropriate methods can be used to monitor
the element included in the circuit 102. For example, the external
monitor circuit 1100 may have the same configuration as the
above-described monitor circuit 700 and operate under an operation
condition that is the same as or close to that of the circuit 102.
It is possible to monitor the degree of performance deterioration
of the element included in the circuit 102 based on the information
of oscillation information measured by an oscillation circuit
arranged in the external monitor circuit 1100, and supply the
signal 104 to the controller 105.
[0072] Also, for example, the external monitor circuit 1100 may
monitor operation conditions such as the temperature, the operating
voltage, the total current-carrying time, and/or the toggle rate of
the element included in the circuit 102. According to the result of
monitoring at least one of the operation conditions of the circuit
102, the external monitor circuit 1100 may obtain the state of
performance deterioration such as degradation of the element
included in the circuit 102 and supply the signal 104 to the
controller 105. The external monitor circuit 1100 may calculate the
state of the element included in the circuit 102 based on the
monitor results of the operation conditions of the circuit 102 and
generate the signal 104. The external monitor circuit 1100 may
generate the signal 104 by referring to, for example, a lookup
table recorded in advance and representing the relationship between
the operation conditions and the degree of performance
deterioration of the circuit 102.
[0073] In the above-described embodiment, a case in which one set
of the circuit 102 including an element that is a redundancy
target, the circuit 103 including an element that makes the circuit
102 redundant, and the controller 105 that controls the circuit 103
is included in the integrated circuit 101 is shown. However, the
combination of the circuits 102 and 103 and the controller 105
included in the integrated circuit 101 is not limited to one set,
and a plurality of sets may be arranged in the integrated circuit
101. A configuration shown in FIG. 12 shows an example of the
integrated circuit 101 including two sets of circuits 102 and 103
and the controllers 105. FIG. 12 shows an example of a
configuration including two sets of circuits 102 and 103 and the
controllers 105. However, the integrated circuit 101 may include
three or more sets of the above-described combinations.
[0074] A circuit 102a, a circuit 103a, and a controller 105a shown
in FIG. 12 function as one set to execute a predetermined
operation. Similarly, a circuit 102b, a circuit 103b, and a
controller 105b function as one set to execute a predetermined
operation. Signals 104a and 104b representing a state such as
performance deterioration of elements included in the circuits 102a
and 102b during an operation may be supplied to the controllers
105a and 105b by the monitor circuit 700 arranged in the integrated
circuit 101, as described above.
[0075] FIG. 13 is a block diagram in a case in which the signals
104a and 104b are generated by the monitor circuit 700 arranged in
the integrated circuit 101 in the configuration shown in FIG. 12.
The monitor circuit 700 may be a circuit common to the circuits
102a and 102b as the redundancy targets. However, as described
above, the possibility that the monitor circuit 700 can correctly
detect the degree of performance deterioration such as degradation
of the elements included in the circuits 102a and 102b is high when
the condition such as a voltage or a temperature at the time of an
operation for the monitor circuit 700 is close to that of the
circuits 102a and 102b. Hence, in the configuration shown in FIG.
13, a monitor circuit 700a and a monitor circuit 700b are arranged
in the integrated circuit 101. The monitor circuit 700a monitors
the state of the circuit 102a, generates the signal 104a in
accordance with the degree of performance deterioration of the
element included in the circuit 102a, and supplies the signal 104a
to the controller 105a. Similarly, the monitor circuit 700b
monitors the state of the circuit 102b, generates the signal 104b
in accordance with the degree of performance deterioration of the
element included in the circuit 102b, and supplies the signal 104b
to the controller 105b.
[0076] The physical arrangement of the monitor circuit 700a in the
integrated circuit 101 will be described here. As described above,
in the integrated circuit 101, a gradient of the voltage or
temperature of a power supply occurs depending on physical
coordinate positions. The magnitude of the degradation of an
element such as a transistor included in the circuit 102a changes
depending on a condition such as a voltage or a temperature. Hence,
when the condition such as a voltage or a temperature for the
monitor circuit 700a is made close to that of the circuit 102a as
the redundancy target, the monitor circuit 700a can more correctly
detect the state of the element included in the circuit 102a.
[0077] Hence, distance 3 between the monitor circuit 700a and the
element included in the circuit 102a may be shorter than distance 4
between the monitor circuit 700a and the element included in the
circuit 102b. When distance 3 is shorter than distance 4, the
conditions such as temperatures or voltages applied to the monitor
circuit 700a and the element included in the circuit 102a are
closer than the conditions for the monitor circuit 700a and the
circuit 102b. Hence, the monitor circuit 700a can more correctly
detect the state of the element included in the circuit 102a. As
for the physical arrangement of the circuit 102b and the monitor
circuit 700b that monitors the state of the circuit 102b as well,
when these are arranged like the circuit 102a and the monitor
circuit 700a, the monitor circuit 700b can more correctly detect
the state of the element included in the circuit 102b. For example,
the monitor circuit 700a may be adjacently arranged to be adjacent
to the circuit 102a, and the monitor circuit 700b may be similarly
adjacently arranged to be adjacent to the circuit 102b.
[0078] In the configurations shown in FIGS. 12 and 13, the
controllers 105a and 105b configured to control the circuits 103a
and 103b are separately arranged. However, the present invention is
not limited to this. One controller 105 may be arranged in the
integrated circuit 101, and the controller 105 may control the
element included in the circuit 103a in accordance with the signal
104a and control the element included in the circuit 103b in
accordance with the signal 104b.
[0079] The signals 104a and 104b may be supplied to the controllers
105a and 105b by the external monitor circuit 1100 arranged
separately from the integrated circuit 101, as described above. At
this time, the external monitor circuit 1100 may be a combination
of an external monitor circuit corresponding to the circuit 102a
and an external monitor circuit corresponding to the circuit 102b.
The external monitor circuit 1100 may be a circuit in which a
circuit corresponding to the circuit 102a and a circuit
corresponding to the circuit 102b are put into one. The external
monitor circuit 1100 can have any configuration if the signals 104a
and 104b corresponding to the states of the circuits 102a and 102b
can be generated.
[0080] Another modification of the above-described embodiment will
be described here. For example, the signal 104 used to notify the
state of the circuit 102 shown in FIG. 1 can be replaced with
another signal inside the integrated circuit 101. The other signal
can be, for example, a signal representing the total
current-carrying time of the integrated circuit 101 itself, a
signal representing a temperature, a signal representing an
operation mode, or the like. For example, the other signal may be a
signal representing the state of a circuit (element) different from
the circuit 102 arranged in the integrated circuit 101 separately
from the above-described monitor circuit 700, for example, a signal
representing the total current-carrying time of the circuit, a
signal representing a temperature, a signal representing an
operation mode, or the like. The circuit may be a circuit
configured to execute the same operation as the circuit 102, or may
be a circuit configured to execute a different operation. The state
of the circuit 102 can be predicted not only from the signal 104
representing the state of the circuit 102 but also from these
signals representing the state of the integrated circuit 101. In
other words, these signals different from the signal 104 can be
signals (deterioration signals) representing the degree of
performance deterioration of the circuit 102. Hence, the controller
105 may perform the determination of step S202 in FIG. 2 using the
signal representing the state of the integrated circuit 101 in
place of the signal 104 or using both the signal 104 representing
the state of the circuit 102 and the signal representing the state
of the integrated circuit 101.
[0081] Similarly, the external monitor circuit 1100 shown in FIG.
11 may be replaced with another circuit arranged in the
semiconductor device 100, which is associated with the information
of operation conditions such as the temperature, the operating
voltage, the total current-carrying time, and the toggle rate of
the element included in the circuit 102. In some cases, a circuit
associated with these pieces of information exists in the
semiconductor device 100. Hence, the internal signal of the circuit
associated with the information of the state of the circuit 102 can
be used in place of the signal 104. Also, for example, in the
configuration shown in FIG. 12, the signals 104a and 104b can be
replaced with other signals of a circuit associated with the
information of the state of the circuit 102 arranged in the
integrated circuit 101. The other signals can be, for example,
signals of a circuit different from the circuit 102, which
represent information associated with the total current-carrying
time, the temperature, the operation mode, and the like of the
circuit 102.
[0082] Also, in the configuration shown in FIG. 3, only one line of
clock tree 303 configured to ensure redundancy is arranged.
However, a plurality of lines of clock trees 303 may be arranged,
as described above. In this case, the number of clock trees 303 to
be used in parallel may be controlled in accordance with the
magnitude of degradation of the clock tree 302. When controlling
the number of clock trees 303 to be used in parallel, the signal
104 is a multi-valued signal, and the control signal 106 supplied
from the controller 105 to the clock tree 303 based on the signal
104 is a multi-valued signal as well. This makes it possible to
change (control) the number of clock trees 303 to be used in
parallel.
[0083] Similarly, in the configuration shown in FIG. 4, the
controller 105 may control the number of power shutdown switches
405 that tare included in the power shutdown switch group 403 and
are to be operated in parallel in accordance with the state
(performance deterioration) of the power shutdown switch group 402.
In this case, the signal 104 output in accordance with performance
deterioration is a multi-valued signal, and the control signal 106
supplied from the controller 105 to the power shutdown switch group
403 based on the multi-valued signal 104 is a multi-valued signal.
This makes it possible to change (control) the number of power
shutdown switches 405 to be used in parallel. In addition, a
plurality of power shutdown switch groups 403 may be arranged, and
the number of power shutdown switch groups 403 or the number of
power shutdown switches 405 to be operated in parallel with the
power shutdown switch group 402 may be changed.
[0084] Also, in the configuration shown in FIG. 5, a plurality of
driving circuits 512 may be arranged, and the controller 105 may
control the number of driving circuits 512 to be operated in
parallel in accordance with the state (performance deterioration)
of the driving circuit 511. In this case, the signal 104 output in
accordance with performance deterioration is a multi-valued signal,
and the control signal 106 supplied from the controller 105 to the
driving circuit 512 based on the multi-valued signal 104 is a
multi-valued signal. This makes it possible to change (control) the
number of driving circuits 512 to be used in parallel.
[0085] Furthermore, the semiconductor device 100 may be configured
to operate in a plurality of operation modes. That is, in some
cases, the integrated circuit 101 may switch a plurality of
operation modes different from each other and operate in each
operation mode. For this reason, the operation of the integrated
circuit 101 of the semiconductor device 100 shown in FIG. 2 may be
executed not only at the time of power-on but also, for example,
every time the operation mode of the integrated circuit 101 is
switched. This is because the speed and amount of performance
deterioration of the circuit 102 and the type of circuit 103 to be
operated for redundancy may change depending on the operation mode
in which the integrated circuit 101 operates.
[0086] As for the switching of the operation mode, for example, a
case in which the integrated circuit 101 is operated in two
operation modes including a power saving mode and a high-speed
signal processing mode in redundancy of the clock tree shown in
FIG. 3 can be considered. The high-speed signal processing mode can
be a mode used to improve the processing capability of the
integrated circuit 101 as compared to the power saving mode by
making the power supply voltage higher than in the power saving
mode and raising the clock frequency. In the high-speed signal
processing mode, the performance deterioration of the clock tree
302 may be larger than in the power saving mode. Also, in the
high-speed signal processing mode, signal processing faster than in
the power saving mode is required. Hence, the number of circuits to
be operated for redundancy may change, more specifically, increase.
In other words, there can be cases in which a plurality of clock
trees 303 are arranged in parallel, and more clock trees 303 are
operated in the high-speed signal processing mode than in the power
saving mode, thereby performing faster signal processing. Hence,
the procedure shown in FIG. 2 may be executed when switching the
operation mode of the integrated circuit 101.
[0087] FIG. 14 is a timing chart showing an example of the
operations of the circuits 102 and 103 when switching the operation
mode of the integrated circuit 101 from the high-speed signal
processing mode to the power saving mode. The circuit 102 always
continues the operation, as described above. On the other hand, the
circuit 103 may start the operation at the timing to be described
below in the power saving mode and the high-speed signal processing
mode.
[0088] As shown in FIG. 14, the circuit 103 is at stop
(non-operation) at time t1 when the operation is started in the
high-speed signal processing mode. Next, at time t2, the circuit
103 receives the control signal 106 from the controller 105 and
starts the operation. At time t3, when the operation mode of the
integrated circuit 101 switches to the power saving mode, the
controller 105 transmits the control signal 106 for setting the
circuit 103 in the non-operation state to the circuit 103, and the
circuit 103 stops the operation in accordance with the control
signal 106 and transitions to the non-operation state. Next, at
time t4, the circuit 103 receives the control signal 106 from the
controller 105 and starts the operation. As shown in FIG. 14, the
time from time t1 when the integrated circuit 101 starts the
operation in the high-speed signal processing mode to time t2 when
the circuit 103 starts the operation can be shorter than the time
from time t3 when the operation mode switches, and the integrated
circuit 101 starts the operation in the power saving mode to time
t4 when the circuit 103 starts the operation.
[0089] Also, as shown in FIG. 14, since the circuit 103 is set in
the non-operation state every time the operation mode is switched,
and operates at the timing when the performance of the circuit 102
as the redundancy target deteriorates, and the operation of the
circuit 103 is necessary, the time of the operation shortens. This
can suppress performance deterioration of the circuit 103
configured to make the circuit 102 redundant. In addition, since
the circuit 103 does not operate during the period from time t1 to
time t2 and during the period from time t3 to time t4, for example,
a recovery effect for degradation caused by NBTI is generated, and
the degradation of the circuit 103 can recover. For this reason,
when the circuit 103 is operated at a timing appropriate for each
operation mode of the integrated circuit 101, the operation of the
integrated circuit 101 can be guaranteed for a longer period, and
the reliable semiconductor device 100 can be implemented.
[0090] The high-speed signal processing mode can correspond to, for
example, a high resolution mode in which data of a large number of
pixels is processed by a data processing circuit of a photoelectric
conversion system such as a camera. The power saving mode can
correspond to a live view mode in which image capturing data is
displayed on a viewfinder or a display by a data processing circuit
of a photoelectric conversion system such as a camera. If the image
capturing mode is switched in a photoelectric conversion system
such as a camera, for example, the frequency of a clock to be
supplied is changed without changing the operating voltage in some
cases. In this case as well, when the operation mode is switched,
the above-described operation is performed, thereby operating the
circuit 103 arranged to make the circuit 102 redundant only during
a necessary period. This makes it possible to ensure high
reliability for a long time in the semiconductor device 100
including the integrated circuit 101.
[0091] As described above, the semiconductor device 100 according
to this embodiment can be applied to a photoelectric conversion
device. A photoelectric conversion system using a photoelectric
conversion device incorporating the semiconductor device 100
according to this embodiment will be described here with reference
to FIG. 15. FIG. 15 is a block diagram showing the schematic
configuration of a photoelectric conversion system 1400 according
to this embodiment.
[0092] The photoelectric conversion device incorporating the
semiconductor device 100 can be applied to various kinds of
photoelectric conversion systems. Examples of photoelectric
conversion systems to which the semiconductor device is applicable
are a digital still camera, a digital camcorder, a monitoring
camera, a copying machine, a facsimile apparatus, a mobile phone,
an in-vehicle camera, and an observation satellite. A camera module
including an optical system such as a lens and a photoelectric
conversion device is also included in the photoelectric conversion
systems. FIG. 15 shows the block diagram of a digital still camera
as an example of these.
[0093] The photoelectric conversion system 1400 shown in FIG. 15
includes a photoelectric conversion device 1404 incorporating the
semiconductor device 100, a lens 1402 that forms an optical image
of an object on the photoelectric conversion unit (for example, the
photoelectric conversion unit 523 shown in FIG. 5) of the
photoelectric conversion device 1404, an aperture 1403 configured
to change the amount of light passing through the lens 1402, and a
barrier 1401 configured to protect the lens 1402. The lens 1402 and
the aperture 1403 form an optical system that condenses light to
the photoelectric conversion device 1404. The photoelectric
conversion device 1404 converts the optical image formed by the
lens 1402 into an electrical signal.
[0094] The photoelectric conversion system 1400 also includes a
signal processing unit 1407 that is an image generation unit
configured to generate an image by processing an output signal
output from the photoelectric conversion device 1404. The signal
processing unit 1407 performs an operation of performing various
kinds of correction and compression as needed, thereby outputting
image data. The signal processing unit 1407 may be formed on a
semiconductor substrate on which the photoelectric conversion
device 1404 is provided or may be formed on a semiconductor
substrate different from the photoelectric conversion device 1404.
In addition, the photoelectric conversion device 1404 and the
signal processing unit 1407 may be formed on the same semiconductor
substrate.
[0095] The photoelectric conversion system 1400 further includes a
memory unit 1410 configured to temporarily store image data, and an
external interface unit (external I/F unit) 1413 configured to
communicate with an external computer or the like. Also, the
photoelectric conversion system 1400 includes a recording medium
1412 such as a semiconductor memory configured to record or read
image capturing data, and a recording medium control interface unit
(recording medium control I/F unit) 1411 configured to perform
record or read for the recording medium 1412. Note that the
recording medium 1412 may be incorporated in the photoelectric
conversion system 1400 or may be detachable.
[0096] Furthermore, the photoelectric conversion system 1400
includes a general control/arithmetic unit 1409 that controls
various kinds of operations and the entire digital still camera,
and a timing generation unit 1408 that outputs various kinds of
timing signals to the photoelectric conversion device 1404 and the
signal processing unit 1407. Here, the timing signal and the like
may be input from the outside, and the photoelectric conversion
system 1400 need only include at least the photoelectric conversion
device 1404, and the signal processing unit 1407 that processes an
output signal output from the photoelectric conversion device
1404.
[0097] The photoelectric conversion device 1404 outputs an image
capturing signal to the signal processing unit 1407. The signal
processing unit 1407 executes predetermined signal processing for
the image capturing signal output from the photoelectric conversion
device 1404, and outputs image data. The signal processing unit
1407 generates an image using the image capturing signal.
[0098] As described above, according to this embodiment, it is
possible to implement the photoelectric conversion system to which
the photoelectric conversion device 1404 (for example, an image
capturing device) incorporating the above-described semiconductor
device 100 is applied.
[0099] A photoelectric conversion system and a transport apparatus
including a photoelectric conversion device incorporating the
semiconductor device 100 according to this embodiment will be
described next with reference to FIGS. 16A and 16B. FIGS. 16A and
16B are block diagrams showing the configuration of a photoelectric
conversion system 1500 incorporating the semiconductor device 100
according to this embodiment and the configuration of a transport
apparatus 1501 incorporating the photoelectric conversion system
1500.
[0100] FIG. 16A shows an example of the photoelectric conversion
system 1500 concerning an in-vehicle camera. The photoelectric
conversion system 1500 includes a photoelectric conversion device
1510 incorporating the semiconductor device 100. The photoelectric
conversion system 1500 includes an image processing unit 1512 that
performs signal processing such as image processing for a plurality
of image data acquired by the photoelectric conversion device 1510,
and a parallax acquisition unit 1514 that calculates a parallax
(the phase difference between parallax images) from the plurality
of image data that have undergone the signal processing by the
image processing unit 1512. The photoelectric conversion system
1500 also includes a distance acquisition unit 1516 that calculates
the distance up to a target based on the calculated parallax, and a
collision determination unit 1518 that determines, based on the
calculated distance, whether there is collision possibility. Here,
the parallax acquisition unit 1514 and the distance acquisition
unit 1516 are examples of a distance information acquisition unit
that acquires distance information up to a target. That is, the
distance information is information concerning a parallax, a
defocus amount, a distance up to a target, and the like. The
collision determination unit 1518 may determine collision
possibility using one of the pieces of distance information. The
distance information acquisition unit may be implemented by
exclusively designed hardware, or may be implemented by a software
module. The distance information acquisition unit may be
implemented by an FPGA (Field Programmable Gate Array) or ASIC
(Application Specific Integrated Circuit), or may be implemented by
a combination of these.
[0101] The photoelectric conversion system 1500 is connected to a
vehicle information acquisition device 1520 of the transport
apparatus 1501 (for example, a vehicle) including a driving device,
and can acquire vehicle information such as a vehicle speed, a yaw
rate, and a steering angle. The photoelectric conversion system
1500 is also connected to a control ECU 1530 that is a control
device configured to output a control signal for generating a
braking force to the vehicle based on the determination result of
the collision determination unit 1518. Also, the photoelectric
conversion system 1500 is connected to an alarm device 1540 that
generates an alarm to the driver based on the determination result
of the collision determination unit 1518. For example, if collision
possibility is high as the determination result of the collision
determination unit 1518, the control ECU 1530 performs vehicle
control of braking, releasing the accelerator pedal, or suppressing
the engine output, thereby avoiding collision and reducing damage.
The alarm device 1540 sounds an alarm, displays alarming
information on the screen of a car navigation system or the like,
applies a vibration to the seat belt or a steering wheel, thereby
making an alarm to the user.
[0102] In this embodiment, the periphery of the transport apparatus
1501, for example, the front or rear side is captured by the
photoelectric conversion system 1500. FIG. 16B shows the
photoelectric conversion system 1500 in a case in which the front
side (image capturing range 1550) of the transport apparatus 1501
is captured. The vehicle information acquisition device 1520 sends
an instruction to the photoelectric conversion system 1500 or the
photoelectric conversion device 1510. With this configuration, it
is possible to further improve the accuracy of distance
measurement.
[0103] An example in which driving devices such as the brake, the
accelerator, and the engine of the transport apparatus 1501 are
controlled based on information obtained by the photoelectric
conversion device 1510 so as not to collide with another vehicle
has been described. However, the present invention is not limited
to this, and the system can also be applied to control of
performing automated driving following another vehicle or control
of performing automated driving without deviating from a lane.
Also, an example in which the photoelectric conversion system 1500
incorporating the semiconductor device 100 is incorporated in the
transport apparatus 1501 has been described. However, the
semiconductor device 100 may be incorporated in the vehicle
information acquisition device 1520, the control ECU 1530, or the
alarm device 1540. The photoelectric conversion system 1500
incorporating the semiconductor device 100 can be applied not only
to a vehicle such as an automobile but also to, for example, a
transport apparatus including a driving device, such as a ship, an
airplane, a railroad vehicle, or an industrial robot. In addition,
the photoelectric conversion system can be applied not only to a
moving body but also to an apparatus that broadly uses object
recognition, such as an intelligent transport system (ITS).
[0104] While the present invention has been described with
reference to exemplary embodiments, it is to be understood that the
invention is not limited to the disclosed exemplary embodiments.
The scope of the following claims is to be accorded the broadest
interpretation so as to encompass all such modifications and
equivalent structures and functions.
[0105] This application claims the benefit of Japanese Patent
Application No. 2020-026468, filed Feb. 19, 2020 and Japanese
Patent Application No. 2020-192667, filed Nov. 19, 2020 which are
hereby incorporated by reference herein in their entirety.
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